Liquid conductor heater



Nov. 3, 1942. M. w. HANKS LIQUID CONDUCTOR HEATER s Sheets- Sheet 1Filed April 25, 1941 Nov. 3, 1942. M, w, HANKS 2,300,891

LIQUID CONDUCTOR HEATER Filed April 25, 1941 I5 Sheets-Sheet 2 INVENTOR.

bmzu M M Nov. 3, 1942. M w, HANKs 2,300,891

LIQUID CONDUCTOR HEATER Filed April 25, 1941 5 sheets sheet INVENTOR.

Patented Nov. 3, 1942 LIQUID CONDUCTOR HEATER Marshall W. Hanks,Madison, Wis., assignor to Hankscraft Company, Madison, Wis., acorporation of Wisconsin Application April 25, 1941, Serial No. 390,261

16 Claims.

This invention relates to improvements in liquid conductorheaters of thetype disclosed, for example, in the United States Patent No. 1,683,071granted to MarshallW. Hanks and Max Mason on September 4, 1928, in whicha pair of spaced electrodes connected in an electric circuit are locatedin a vessel of insulating material and connected by a measured quantityof water or other vaporizable liquid which is adapted to be evaporatedto substantial dryness by the passage of current therethrough, thusgiving the apparatus a substantially definite time period of operation.By suitably regulating the measured quantity of water which is put intothe vessel, the duration of the operation of the apparatus may be variedas desired. The apparatus of the present invention may be used forwarming a babys milk bottle, or cooking eggs, or for heating or cookingvarious other objects for definite time periods which are automaticallyterminated by the evaporation of the water without attention on the partof the operator. This application is a continuation-in-part of copendingapplication Serial No. 156,159, filed July 28, 1937, by the presentapplicant.

The principal object of the present invention is to provide an improvedliquid conductor heater of the type above referred to which will beefficient in operation and which may be conveniently and economicallyconstructed so that it may be supplied to the user at a comparativelylow price.

A further object is to provide an improved construction and mounting ofthe spaced electrodes in a liquid conductor heater.

Still another object is to provide a liquid conductor heater comprisingspaced electrodes which are held in place in a vessel by a clampingplate of insulating material which also serves to protect the fingers ofthe operator from contact with the electrodes.

Another object of the invention is to provide an insulating platecovering these electrodes of a liquid conductor heater and protectingthe fingers of the operator from contact with the electrodes, which isprovided with means for causing any liquid thereon to flow off to apoint where it contacts the electrodes. I

A further obect is to provide a liquid conductor heater comprising avessel having spaced electrodes mounted therein and having an insulatingplate mounted over these electrodes and provided with a cavity forming aboiling space adjacent the electrodes.

Still another object of the invention is to provide improved means forconveniently connecting the electrodes of a liquid conductor heater inan electric circuit.

Another object is to provide improved means for conveniently and quicklyattaching a name plate or cover plate to the vessel of a liquidconductor heater. Other objects relate to various features ofconstruction and arrangement which will appear more fully hereinafter.

The nature of the invention will be understood from the followingspecification taken with the accompanying drawings in which theinvention is illustrated. In the drawings,

Figure 1 shows a perspective view of one form of the improved liquidconductor heater of the present invention, which is shown as being usedfor heating a babys milk bottle;

Fig; 2 shows an enlarged top plan view of the liquid conductor heatershown in Fig. l with the milk bottle removed;

Fig. 3 shows a vertical section taken on the line 3-3 of Fig. 2;

Fig. 4 shows a vertical section taken on the line 4-4 of Fig. 2;

Fig. 5 shows a horizontal section taken on the line 5-5 of Fig. 3;

Fig. 6 shows an enlarged top plan view of the nut or washer which isengaged by a bolt by which the insulating plate is held above theelectrodes;

Fig. '7 shows an enlarged bottom plan view of the electric conductorheater shown in Fig. 1 with a ortion of the bottom cover plate or nameplate removed;

Fig. 8 shows a side elevation of the insulating plate which is mountedover the electrodes;

Fig. 9 shows a bottom plan view of the insulating plate shown in Fig. 8;

Fig. 10 shows an enlarged vertical section on the line ill-l0 of Fig. 7,illustrating the means of connecting the terminals of the electrodeswith the conductors leading from a source of pp y;

Fig. 11 is a side elevation of a modified form of the connectionillustrated in Fig. 10;

Fig. 12 shows a side sectional view of a different embodiment of animproved liquid conductor heater constructed in accordance with thepresent invention;

Fig. 13 shows a shown in Fig. 12;

Fig. 14 shows a bottom shown in Fig. 12 with the moved; and s Fig. 15 isan enlarged sectional view illustrattop plan view of the heater planview of the heater bottom cover plate reing thedetails of theelectrodemcunting assembly utilized in the heater shown in Fig. 12.

Referring nowmore particularlyto Figs. 1 to l1, inclusive, of thedrawings, the embodiment of the invention there illustrated comprises avessel it formed of porcelain or other suitable insulatingmaterial whichis adapted to receive the article or object to be heated or cooked. Inthis instance, a baby's milk bottle I6 is shown mounted in the cavity ofthe vessel. :I'he vessel l has an outer annular wall It, a bottom wallI6, and a lower annular flange or base portion l5 adapted to rest upon atable or other support and forming a bottom cavity l5. in whichconnections are established with a pair of spaced electrodes l1 and IIwhich are located in the bottom or the vessel, resting on the bottomwall 15'. The electrodes l1 and II are preferably formed as bare roundwires of conducting material which are wound in spiral fashion andlocated one within the other so that convolutions of one electrodearelocated on opposite sides of each convolution of the I The convolutionsof the separate electrodes are maintained in place laterally on 'thebottom wall li and are spaced from adjacent convolutions of the otherelectrode by means'of projections Iii other electrode.

'water or other liquids, as it is desirable that all portions of thisliquid reach the electrodes to be heated and vaporized/thus giving theapparatus a definite time periodof operation. The head of. the bolt 2.!is located in a central recess or depression 20' formed in the upperside of the insulating plate and the stem of the bolt extends through. acentral boss 20 from which three flanges or arms20 extend radiallyoutward, being united integrally with the under side of the body of theplate. These flanges or arms 20' are preferably located directly beneaththe fiat portions 2|] upon which the bottle l6 rests, and the loweredges of these flanges 20 are adapted to engage the upper edgeportionsef the electrodes l1 and [8 which are thus clamped between theflanges and the bottom wall W of the vessel.

I The flanges or arms 20' thus form the cavities 20 which are open attheir outer ends and which serve as boiling spaces immediately above theelectrodes so that there is a free opportunity for bubble formation asthe liquid in the vessel is heated and vaporized. The plate 20 ispreferably slightly less in diameter than the internal diameter of thelower portion of the cavity of the vessel so that thereis an annularspace 22.

which areformed integrally with the bottom wall II and which projectupwardly therefrom. These projections I! are preferably arranged in rowsextending radially'o'utward from the cen; ter ofthe vesel as shown inFig. 5. f' i The electrodes l1 and are held in place on the bottom wallII by means of an insulating plate formed of porcelain orother suitableinsulating material which rests upon the upper edges of the electrodesand which is secured in place by a bolt 2| engaging a nut" whlchislocated in a recess II formed'in the upper surface of the-bottomwall IS.The nut 22 is preferably in the form of a flat spring washeras.

shown in Fig. 6,;being notched onone side as is of a diameter shown in22-. This washer slightly greater than the diameter of the upper 1 partof'the circular recess 1 washer is of -a diameter such that it fits thebottom of the spaces between the threads of the bolt, so that the washerforms a one-thread nut. When this washer is pushed downwardly into 5' inthe bottom wall of the vessel, and the'central aperture 22 in this thecement.

the recess i5, it assumes a downwardly convexed shape and is retained inthe recess by the engagement'with the wall thereof and the extremityofthe bolt 2| may be threaded intoengagementtherewith' to hold theinsulating plate 20 in tight engagement with the electrodes l1 and II sothat these electrodes are clamped against the bottom wall of thevessel.-

The insulating cover plate 20 is provided on its upper side with acentral annular surface 20' and three outwardly radiating surfaces 20which gaged by the bottom of the milk bottle is The portions of theinsulating plate between the horizontally "radiating flat portions 20areinclined downwardly as shown at 20, forming radiating troughs 20These troughs are inclined downwardly and outwardly so that'a'ny wateror other vaporizable liquid on the upper surface of the insulating plateis directed downwardly by gravity and flows from the-troughs 20 to thebottom of the vessel where it engages the spaced electrodes II and. II.This is of particula'rimportanee'when the apparatus is being operatedwith a relatively small quantity of fare horizontal and which areadapted to be'enaround the outer edge of the plate 2| to permit .theupwardescape of bubbles which are produced by the heating of the liquid.'In addition, the ready escape of these bubbles is insured by theprovision in the body portion of the plate 20 of a number of apertures20which are preferably located in the inclined portions 20 of the troughs,as shown in Fig. 2.

The electrodes 11 and i8 are connected in a supply circuit byhaving'portions l1 and II' thereof, respectively, led downwardly throughapertures l5 which are formed in the bottom wall of the vessel. Afterinserting these portions of the electrodes through theapertures it, theapertures may be sealed by any suitable waterproof cement which isadapted to withstand any 'heat which may be generated by the passage ofcurrent through the electrodes. If desired, por- 'tions of rubber.tubing may be inserted around the electrodes in the apertures beforeapplying The extremities of the electrodes are connected to supplyconductors 25 and 2! which are surrounded by insulation to form acommon, flexiblecord 21 having at the end thereof a fitting 28, as shownin Fig. l, which permits the connectionof the conductors 2i and 28 in anelectric circuit. In order to connect the extremities of the electrodeswith the conductors 25 and 26, which-have'the insulation removed fromthe inner ends thereof, without the use of screws or other usualfastening means, the bottom wall ii"; of the vessel is provided on itsunderside with a pair of elongated grooves orrecesses' H! which havetheir side walls tapered upwardly. The bare extremities of theconductors 25 and 26 are laid across thesegrooves and then, afterplacing the extremities I1 and Ill of the electrodes transv'erselyacross these extremities of the supply conductors, these portions I1 andi8" of the electrodes are pushed upwardly into the grooves i5, therebyforming U-shaped bends in the extremities of the conductors 25 and 26,as shown in Fig.

, l0, and causingthese conductors to be held in frictional engagementwith the extremities of the electrodes. In order to compensate forvarious diameters of the wires and electrodes which may be employed witha particular vessel-i5, shims 28 of any suitable material may be placedabove the conductors 25 and 28 before the parts are pushed into thegrooves i5. as shown in Fig. 10, and the shims may be selected of anysuitable thickness to cause a tight wedging fit when the parts have beenpushed into the grooves. The conductors 25 and 28 may be prevented fromshifting laterally adjacent the grooves I5 by providing bosses I5 ontheunder side of the bottom wall I5 of the vessel, as shown in Fig. 7. Forthe purpose of locking the insulated portions of the conductors 25 and26 to prevent any tension created in the cord 21 from being transmittedto the connections which have been formed between the conductors and theelectrodes, the conductors 25 and 26 are bent transversely at a pointadjacent the aperture I5" through which the cord 21 is brought throughthe base flange ill of the vessel, and the bottom wall of the vessel isprovided with a locking lug I which is formed integrally with the bottomwall and which has outwardly diverging arms adapted to maintain a sharpbend in each of the conductors 25 and 25 about the projections Ill whichare formed on the inner margin of the base flange I52 as shown in Pig.7.

The connections of the supply conductors with the electrodes arepreferably concealed by a cover plate 30, formed of suitable sheet metalor the like, which seats against the annular shoulder I5 which is formedon the inner portion of the base flange of the vessel. In order thatthis cover plate may be secured to the vessel without the use of screwsor other usual fastening means,

the base of the vessel is provided with a project-' ing boss I5 adaptedto engage an aperture 30 formed in the cover plate 30. The boss I5 maybe located anywhere on the base above the cover plate, but in thisinstance it is formed as an extension of the lugs I5 and is hexagonal incross section so that it has corners which are adapted to bite into themetal on the edges of the circular aperture which is formed in the coverplate. This aperture 30 is of such size that when the cover plate isdriven upwardly over the boss the metal will interlock with theporcelain of the boss l5 and thus hold the cover plate in place. Thiscover plate may serve as a name plate for the manufacturer and also tocarry printed directions for the operation of the apparatus.

In Fig. 11. there is shown a simple form of connection which may be usedas a substitute for the connection shown in Fig. 'l to attach the supplyconductors to the electrodes. With this arrangement, a supply conductor32 has its extremity twisted around the end of an electrode 22 and theextremity of this electrode is reversely bent as shown at 33" to enclosethe twisted portion of the conductor.

The second embodiment of the invention as illustrated in Figs. 12 to 15,inclusive, of the drawings is substantially similar in'construction andarrangement with the first embodiment of the invention as describedabove. Briefly described. the second embodiment of the inventioncomprises a vessel H5 formed of molded porcelain or other suitableinsulating material, which is provided with an outer annular wall IIS",a bottom wall H5". and a lower annular flange or base portion 5. Thebottom wall Iili and the flanged portion II5 define a bottom cavity H5within which connections are established with a pair of pin receivingsockets IIlI and Iii". The sockets BI" and I3i are adapted to receiveand grip a pair of contact pins i32 and I32 which electrically terminatethe respective inner ends of the two electrodes Ill and H8. These twoelectrodes are interposed between the upper surface of the bottom wallII5- and the under surface of a supporting member I20 which is alsoformed of molded porcelain or other suitable insulating material. Morespecifically, the electrodes H1 and H8, which may be formed of bareround wires or ribbon stock of conducting material. are wound in spiralfashion one within the other. and the intermeshed convolutions thereofare secured to the under surface of the supporting member I20. To thisend. the member I20 is provided with an under surface which includesfour integrally formed separating elements in the form of downwardlyprojecting ribs I20". These ribs extend radially outward from the centerof the member I20 and adjacent ones thereof are normal to each other. Inorder to space the convolutions of the electrodes III and H8 apart alongthe ribs I20". transversely extending slots may be formed in the undersurface of the ribs into which the electrodes may be wedged or otherwisesecured. Alternatively. the electrodes may be imbedded in the ribs withthe convolutions thereof suitably spaced apart, during the molding ofthe member I20. The inner ends of the electrodes Ill and H8 are eachlooped through two openings provided in the member I20 in order tosecurely hold the electrodes on the under surface of this member. Morespecifically. the electrode H8 is provided with a substantially U-shapedinner end portion H8" which encircles the portion I20 of the member I20.The electrode III is similarly provided with a substantially U-shapedinner end H1 which is looped over the portion I20 of the member I20. Theinner legs of the Ushaped electrode portions III" and H8 extend into andare soldered to the pin connectors I32 and I32, respectively. These pinsconnectors are rigidly secured to the insulating member I20 in anydesired manner, although preferably the arrangement shown in Fig.' isused. As there shown, the connector I32 is provided with an enlargedbase which seats in the hole of the member I through which the inner legof the electrode portion Ill extends. The right top side of this baseportion is spun over to enga e the upper surface of the ledge I20". Foursmall fingers I32 bent out from the stem of the connector are providedwhich engage the under side of the member I20. It will be noted from theabove explanation that the base legs of the U-shaped end portions Illand II8 of the two electrodes lie in deep narrow channels formed in theupper surface of the insulating member I20. It will also be noted thatthe electrodes are entirely covered by the insulating member I20. Thisarrangement precludes the possibility of a user of the apparatus comingin contact with the electrodes.

The two sockets I3I and IIli are U-shaped in contour, are relativelywide as compared with the diameter of the pin connectors I32 and I32",and are constructed of spring metal such as bronze strip. These twosockets are soldered to the two bare ends of the cord conductors I andI26. re pectively. These conductors are sharply looped around strainposts I31" and I33". which are suitably secured to the under side of thebottom wall Iii: and which prevent the conductor ends from being pulledout of the sockets I22- and I32". The two sockets are rigidly held inplace by cementing the same to the bottom wall of the vessel at ill inthe manner illustrated, thus providing a liquid tight seal over thebottom ends of the two holes in which the sockets are disposed.

As best shown in Fig. 12 of the drawings, the inner central portion ofthe bottom wall il5 is provided with a raised portion H5". Between thisportion of the vessel and the outer wall 5* thereof, an annular liquidreceiving well H5 is defined. This well is of the correct dimensions toreceive the radially extending ribs I upon which the two electrodes Illand iii! are mounted. The raised portion N5 of the bottom wall llti isadapted to engage the central under surface of the insulating member i20for the purpose of supporting this member. Preferably, the dimensionsare such that the ribs I20 and the electrodes carried thereby areslightly above the upper surface of the bottom wall H5.

The upper or supporting surface of the insulating member I2!) ispreferably identical in .contour with that of the insulating mem er I20forming a part of the first described embodiment of the invention,except that four troughs are provided therein instead of the threetroughs used in the construction shown in Figs. 1 to 11, inclusive. Inorder to facilitate removal of the member in from the vessel H5, twofinger receiving notches I20 are provided in the upper sur-. facethereof. The member I20 is preferably slightly less in diameter than theinternal diameter of the lower portion of the cavity of the vessel H5 sothat an annular space is provided around the outer edge of the memberwhich permits the upward escape of bubbles that are produced by theheating of the liquid. In addition, the ready escape of these bubbles isinsured by providing in the body portion of the plate a number ofapertures ilil' which are preferably located in the inclined portions ofthe troughs, as shown in Fig. 13 of the drawings.

Although two embodiments of the invention have been shown and describedby way of illustration, together with a modification of the connectionbetween the electrodes and the supply conductors, it will be understoodthat the inventlon may be constructed in various other embodiments whichcome within the scope of the appended claims.

I claim:

1. A liquid conductor heater comprising a vessel adapted to contain ameasured quantity of liquid, a pair of spaced electrodes in said vesseladapted to be connected by said liquid, and an insulating member mountedover said electrodes and having an upper surface provided with flathorizontal portions and intervening downwardly and outwardly slopingportions to permit said liquid to flow therefrom.

2. A liquid conductor heater comprising a vessel adapted to contain ameasured quantity of liquid, a pair of spaced electrodes in said vesseladapted to be connected by said liquid, and an insulating member mountedover said electrodes and having horizontal outwardly radiating por'tions arranged alternately with downwardly and outwardly slopingportions.

3. A liquid conductor heater comprising a vessel adapted to contain ameasured quantity of liquid, a pair of spaced electrodes in said vesseladapted to be connected by said liquid, and an insulating member mountedin and secured to said vessel to hold said electrodes in position, saidinsulating member having a cavity therein adjacent said electrodes.

4. A liquid conductor heater comprising a vesscl adapted to contain ameasured quantity of liquid, 2. pair of spaced electrodes mounted insaid vessel and adapted to be connected by said liquid, and aninsulating member mounted over said electrodes and having downwardlyextending outwardly radiating flanges On its under side engaging saidelectrodes to hold them in place, said flanges spacing the body portionof said in sulating member from said electrodes to provide boilingspaces.

5. A liquid conductor heater comprising a vessel adapted to contain ameasured quantity of liquid, a pair of spaced electrodes mounted in saidvessel and adapted to be connected by said liquid, and an insulatingmember mounted over said electrodes and having downwardly extendingoutwardly radiating flanges on its under side engaging said electrodesto hold them in place, said flanges spacing the body portion of saidinsulating member from said electrodes to provide boiling spaces, saidinsulating member having apertures therethrough between said flanges.

6. A liquid conductor heater comprising a vessel adapted to contain a.measured quantity oi liquid, a pair of spaced electrodes mounted in saidvessel and adapted to be connected by said liquid, and an insulatingmember mounted over said electrodes and having downwardly extendingoutwardly radiating flanges on its under side engaging said electrodesto hold them in place. said flanges spacing the body portion of saidinsulating member from said electrodes to provide boiling spaces, saidinsulating member being of lesser area than the chamber of said vessel.

7. A liquid conductor heater comprising a vessel of insulating materialadapted to contain a measured quantity of liquid, said vessel having abottom wall, a pair of electrodes arranged in spiral fashion on saidbottom wall within said vessel and having their convolutions spaced fromeach other, an insulating member mounted over and resting on saidelectrodes to hold them in position, and means for securing saidinsulating member to said bottom wall.

8. A liquid conductor heater comprising a vessel of insulating materialprovided with a bottom wall having upwardly extending lugs formedthereon, a. pair of electrodes arranged in spiral fashion on the saidbottom wall and having their convolutions spaced from adjacentconvolutions by said lugs, an insulating member having parts thereofresting on both of the said electrodes. and means for securing saidinsulating member in position.

9. A liquid conductor heater comprising a vessel of insulating materialhaving a bottom wall, spaced electrodes mounted on said bottom wall, aninsulating member mounted over said electrodes, said bottom wall havinga recess therein, a thin metal washer mounted in said recess, and athreaded member passing through said insulating member and engaging saidwasher.

10. A liquid conductor heater comprising a vessel of insulating materialhaving a bottom wall provided with a recess therein. electrodes mountedin the bottom of said vessel. an insulating member mounted over saidelectrodes, 11 metal washer of larger area than the said recess pressedinto said recess, and a bolt engaging said insulating member andthreaded into engagement with said washer.

11. A liquid conductor heater comprising a vessel of insulating materialhaving a bottom wall provided with an aperture therethrough and with agroove in the under side of said bottom wall,

an electrode mounted in said vessel and having a part extending throughsaid aperture, a supply conductor having an extremity extendingtransversely to the extremity of said electrode, said conductor and saidelectrode being pressed into said groove to force them into tightwedging engagement with each other.

12. A liquid conductor heater comprising a vessel of insulatingmaterial, a pair of spaced electrodes mounted in said vessel and havingextremities extending through the bottom of said vessel, a pair ofsupply conductors having connections with the extremities of saidelectrodes beneath said vessel, said vessel being provided with integralprojections adapted to engage opposite sides of and bend said conductorsto cause longitudinal strains on said conductors to be received by saidvessel independently of said connections.

13. A liquid conductor heater comprising a vessel of insulatingmaterial. a pair of electrodes mounted in said vessel, supplyconductors, said supply conductors having connections with saidelectrodes beneath the bottom wall of said vessel, said vessel having abase flan e extending downwardly from said bottom wall around saidconnections, and a cover plate seated against parts 01' said baseflange, said vessel having an integral projecting lug, said cover platehaving an aperture adapted to form an interlocking connection with saidlug on said vessel to hold said cover plate in position independently ofother fastening means.

14. A liquid conductor heater comprising a vessel formed of insulatingmaterial and provided with a bottom wall, a member supported by thebottom wall of said vessel and adapted to support objects disposedwithin said vessel for heating, a pair of electrodes comprising spirallyarranged spaced apart convolutions interposed between the upper surfaceof said bottom wall and the under surlace of said member and contactingone of said surfaces. said member being formed of insulating materialand being shaped entirely to cover the convolutions of said electrodes,thereby positively to prevent a user of said heater from contacting saidelectrodes, and means for securing said electrodes to said one surface.

15. A liquid conductor heater comprising a vessei formed of insulatingmaterial and provided with a bottom wall, a member supported by thebottom wall of said vessel and adapted to support objects disposedwithin said vessel for heating, a pair of electrodes comprising spirallyarranged spaced apart convolutions interposed between the upper surfaceof said bottom wall and the under surface of said member, said memberbeing formed of insulating material and being shaped entirely to coverthe convolutions of said electrodes, thereby positively to prevent auser of said heater from contacting said electrodes, one of saidsurfaces being provided with integrally formed separating elements formaintaining the spacing between the convolutions of said electrodes, andmeans for mounting said electrodes upon said one surface.

16. A liquid conductor heater comprising a vessel formed of insulatingmaterial and provided with a bottom wall, a pair of electrodescomprising spaced apart spirally arranged convolutions disposed withinsaid vessel adjacent the upper surface of said bottom wall, a memberhaving an under surface contacting said convolutions and being adaptedto support objects disposed within said vessel for heating, said memberbeing formed of insulating material and being shaped entirely to coverthe convolutions 01' said electrodes, thereby positively to prevent auser of said heater from contacting said electrodes, means includingseparating elements integral with at least a portion of one of saidsurfaces for holding the convolutions of said electrodes on said onesurface in spaced apart relation, and means for detachably securing saidmember to the bottom wall of said vessel.

MARSHALL W. HANKS.

